Before it goes in the pan. A thin layer. That's how you get the bread nice and crispy. Make sure your bread isn't too thick and use a cheese with a low melting point. Don't be afraid of American if it's from the deli.
so i put some mayo on the bread with garlic (i have a big minced garlic in olive oil jar), put a slice of american cheese, spread some cream cheese on it and then some ham
grill it and enjoy!